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Carbon monoxide

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Carbon monoxide in the home is responsible for a considerable number of deaths each year and for many more cases of sub-lethal poisonings.

Many more people are likely to be exposed and suffer from ill effect, but be unaware of the cause. Yet these deaths and accidents can be prevented: both by greater awareness amongst the public and greater vigilance amongst health professionals of the signs and symptoms of exposure in their patients.


Carbon monoxide is an odourless, colourless gas that not only kills many people each year but causes many more serious injuries. Poisoning by carbon monoxide is almost certainly under-diagnosed and there could be a large number of people being exposed and suffering the ill effects of exposure.

Sources of carbon monoxide

Carbon monoxide is produced by the incomplete combustion of carbon-containing fuel.  Potential sources include:

  • gas (domestic or bottled)
  • coal
  • coke
  • oil
  • wood
  • gas stoves
  • fires and boilers
  • gas-powered water heaters
  • paraffin heaters
  • solid fuel powered stoves
  • boilers
  • room heaters.

Inadequate maintenance leading to poor combustion of fuel and inadequate removal of waste products as a result of blocked and partially-blocked flues and chimneys are the main causes of poisoning. Such faults can occur in all types of property and the idea that carbon monoxide poisoning is limited to poorer homes and student accommodation is false. Newly-occupied houses with gas-powered heating systems are sometimes the site of accidents.

Carbon monoxide can seep into properties via shared flues and chimneys, and people may be poisoned by carbon monoxide produced next door. Extraordinary errors, such as the venting of gas fires into cavity walls, can lead to poisoning of people living above those using the fire. Integral garages can be a source of carbon monoxide if car engines are run without adequate ventilation.

Health Protection Agency - Carbon monoxide general information (external link)

Health Protection Agency - Carbon monoxide awareness (external link)

The Gas Safety Trust (external link)

NHS Direct Wales - Carbon Monoxide Poisoning (external link)

Public Health Wales - Carbon Monoxide (external link)